The maker of the powerful painkiller OxyContin and three of its current and former executives pleaded guilty Thursday to misleading the public about the drug's risk of addiction, a federal prosecutor and the company said.

A dispute over maca, a root that supposedly boosts libido, is just the latest collision between indigenous people and commercial interests over so-called biological prospecting, the growing practice of scouring the globe for exotic plants, microbes and other living things ripe for commercial exploitation.

A federal judge blocked sales of a generic version of blood thinner Plavix on Thursday, finding it unlikely a Canadian pharmaceutical company could prove the patent controlling a drug used by 48 million Americans was invalid.